Recently, fingerprint recognition has been widely applied to mobile devices for authentication. For example, the technology is used to increase security of mobile payment, and fingerprint recognition module is necessary for mobile devices. The fingerprint recognition module is usually built in an integrated circuit (IC) chip because integrated circuit technology can provide sensor unit with small pitch which is advantageous to capture a fingerprint image with high resolution. Because the resolution of the fingerprint image should be at least make most of ridges in the fingerprint image distinguishable, the pitch (centre-to-centre distance) of a two-dimensional capacitive sensor unit is not greater than 50 μm. Since the linewidth is smaller than the pitch, the resistance of the narrow lines is high and the electrical property of the capacitive sensor unit is not satisfied. Moreover, the size of the IC chip with capacitive sensing function should be large enough to cover the fingerprint area. The IC chip in large size results in increasing production cost. Therefore, smaller IC chip is still adopted for cutting down the cost to provide a competitive product. However, such capacitive sensor unit is too small to capture an entire fingerprint image. Therefore, rapid and correct fingerprint recognition requires additional complicated technologies while adopting the smaller IC chip. It is desired to capture the entire fingerprint image with high resolution quickly and easily at low cost.